Elevator Safety Chain Control for Automatic Hoistway Service Mode
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Solution Overview
Problem
Existing elevator systems require manual activation of safety modes by service personnel before entering the hoistway, leading to potential human error and safety risks if not performed correctly.
Innovation Solution
A safety system that automatically switches the elevator into a special operating mode when both even and odd landing signals indicate open doors, deploying safety measures like brakes and barriers to protect service personnel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual activation of service mode is required, then service personnel can control safety mode activation, but human error may occur and safety risks increase
Solution Approach 1:
The system automatically detects when service personnel are in the hoistway through safety chain signals from landing doors and autonomously activates service mode, eliminating the need for manual activation. The controller monitors safety chain interruptions and self-determines when protective measures are needed, reducing human error while maintaining safety.
Solution Approach 2:
The system performs preliminary detection of service personnel presence via safety chain monitoring before actual service work begins. By detecting open landing doors and safety chain status in advance, the system proactively activates service mode and safety measures before any hazardous situation can develop.
2Reliability
If automatic service mode activation is implemented, then human error is reduced, but system complexity increases
Solution Approach 1:
The existing safety chain, originally designed for door position monitoring, is repurposed to also detect service personnel presence. The same safety chain infrastructure that monitors landing door positions now dual-functions to trigger service mode activation, avoiding additional complex hardware while improving safety automation.
Solution Approach 2:
The controller continuously monitors feedback from safety chain switches at various landings and automatically adjusts system mode based on this information. When the safety chain is interrupted (indicating open doors and potential service personnel presence), the controller receives feedback and autonomously activates service mode with appropriate safety measures.
3Reliability
If safety measures are automatically deployed, then service personnel protection is enhanced, but response time may be delayed
Solution Approach 1:
The system continuously monitors safety chain status in real-time, maintaining readiness to activate service mode instantly when service personnel are detected. By having the detection system already in place and active, there is no delay in recognizing the need for safety measures - the system is prepared to respond immediately upon detecting open landing doors.
Solution Approach 2:
The controller receives continuous feedback from safety chain switches and responds immediately when service personnel presence is detected. The real-time monitoring and instant feedback loop ensures that safety mode activation occurs without measurable delay, as the system is constantly aware of the hoistway status and can react instantly to changes.
Data Source
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AI summary
A safety system (105) for an elevator system (100) which comprises a hoistway (104), an elevator car (102) and a plurality of landing doors (112a-f) is disclosed. The safety system (105) comprises a first safety chain (120), a second safety chain (125) and a controller (110). The first safety chain (120) is configured to produce an even landing signal and the second safety chain (125) is configured to produce an odd landing signal. The controller (110) is configured to automatically instruct the elevator system (100) to enter a special operating mode when the production of the even landing signal and the odd landing signal indicates that the elevator car (102) is located at an even landing and an odd landing door is open, or that the elevator car (102) is located at an odd landing and an even landing door is open.